Precipitation variation: a key factor regulating plant diversity in semi-arid livestock grazing lands

Yantao Wu; Hao Li; Jiahe Cui; Ying Han; Hangyu Li; Bailing Miao; Yongkang Tang; Zhiyong Li; Jinghui Zhang; Lixin Wang; Cunzhu Liang

doi:10.3389/fpls.2024.1294895

Precipitation variation: a key factor regulating plant diversity in semi-arid livestock grazing lands

Front Plant Sci. 2024 Feb 28:15:1294895. doi: 10.3389/fpls.2024.1294895. eCollection 2024.

Authors

Yantao Wu^{1

2}, Hao Li², Jiahe Cui^{2

3}, Ying Han², Hangyu Li², Bailing Miao⁴, Yongkang Tang⁵, Zhiyong Li², Jinghui Zhang², Lixin Wang², Cunzhu Liang²

Affiliations

¹ College of Life Sciences, Inner Mongolia University, Hohhot, China.
² Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Ministry of Education of China, Collaborative Innovation Center for Grassland Ecological Security, School of Ecology and Environment, Inner Mongolia University, Hohhot, Inner Mongolia, China.
³ College of Resources Environment and Tourism, Capital Normal University, Beijing, China.
⁴ Inner Mongolia Meteorological Institute, Hohhot, China.
⁵ Alxa League Meteorological Bureau, Bayanhot, China.

Abstract

Livestock presence impacts plant biodiversity (species richness) in grassland ecosystems, yet extent and direction of grazing impacts on biodiversity vary greatly across inter-annual periods. In this study, an 8-year (2014-2021) grazing gradient experiment with sheep was conducted in a semi-arid grassland to investigate the impact of grazing under different precipitation variability on biodiversity. The results suggest no direct impact of grazing on species richness in semi-arid Stipa grassland. However, increased grazing indirectly enhanced species richness by elevating community dominance (increasing the sheltering effect of Stipa grass). Importantly, intensified grazing also regulates excessive community biomass resulting from increased inter-annual wetness (SPEI), amplifying the positive influence of annual humidity index on species richness. Lastly, we emphasize that, in water-constrained grassland ecosystems, intra-annual precipitation variability (PCI) was the most crucial factor driving species richness. Therefore, the water-heat synchrony during the growing season may alleviate physiological constraints on plants, significantly enhancing species richness as a result of multifactorial interactions. Our study provides strong evidence for how to regulate grazing intensity to increase biodiversity under future variable climate patterns. We suggest adapting grazing intensity according to local climate variability to achieve grassland biodiversity conservation.

Keywords: grassland ecosystems; grazing intensity; meta-community; precipitation concentration index; sheep; species richness; standardized precipitation evapotranspiration index.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was supported by the National Natural Science Foundation of China (32271656, U22A20559, 31960261), the National Key Research and Development Program of China (2022YFF130060102) and the science and technology plan project of Inner Mongolia Autonomous Region (2020GG0092).